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Firefighters moved out of way just before section of interstate collapsed

One school system cancels Friday classes

Atlanta (CNN)An elevated section of northbound Interstate 85, a major north-south artery for the Southeast, collapsed Thursday evening in Atlanta after a massive fire, officials said.

Atlanta Mayor Kasim Reed said the collapse is not related to terrorism.

"We've spoken to the special agent in charge of FBI, there is no evidence this is related to terrorism," he said Thursday night.

Reed declined to say what caused the collapse, adding that an investigation is underway. There were no fatalities, he said.

"I think it's as serious a transportation crisis as we could have," Reed said.

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The city is looking at traffic plans from the 1996 Olympics to figure out a way forward, Reed said.

Lanes closed

All five lanes of the highway in each direction were blocked and will be closed for the foreseeable future, officials said.

That prospect sent shudders through metro Atlanta commuters, who already contend with heavy traffic. An estimated 250,000 vehicles drive daily through that stretch of I-85, according to the Georgia Department of Transportation.

Officials scrambled to come up with alternate routes and encouraged riders to use public transit.

Cortez Stafford, a spokesman with the Atlanta Fire Department, said a unit was returning from another fire when it saw heavy smoke coming from under I-85.

"There was a 40-feet or higher wall of fire. Power lines were falling and arcing heavily and falling in the streets," Stafford told CNN.

The elevated span of highway -- a few miles north of downtown -- collapsed about 7 p.m. as crews battling the fire got out of danger. The cause of the fire was not immediately known.

McLaughlin slowly followed the taillights of an SUV through the smoke. After about 50 yards, McLaughlin could see clearly again. It smelled like an engine fire, he said.

The smoke blew over a nearby shopping center and had a pungent smell of fuel, CNN's Joe Sutton said.

MARTA, Atlanta's rail and bus system, said it would offer extended service through the weekend.

One school district, in nearby DeKalb County, canceled classes for Friday. Schools in Atlanta will be open, Mayor Kasim Reed said, but city offices won't open until 10 a.m. State offices will open at the same time.

Next week is spring break for many schools in the Atlanta metropolitan area.

Weeks of repair ahead

Reginald DesRoches, a professor at Georgia Tech, said most structural materials lose strength when subjected to high temperature.

He said it is too early to say how long it will take to repair the highway.

"It certainly can take anywhere from several weeks to several months," he said. "The surrounding sections of the highway will be evaluated to determine if any damage was sustained from the heat. It is probably prudent to check both sides of the adjacent sections (northbound and south bound)."